Multi-port bidirectional converter

Abstract

A multi-port bidirectional converter includes a transformer, a primary full-bridge converter, first and second high-voltage power conversion units, first and second low-voltage power conversion units, a full-bridge diode rectifier, and a full-bridge inverter. The transformer comprises a magnetic core, a primary winding and five secondary windings. The primary full-bridge converter is coupled to the first primary winding and receives an input voltage. The first / second high-voltage power conversion unit is coupled to the first / second secondary winding and outputs the first / second high DC voltage to a first / second high-voltage battery. The first / second low-voltage power conversion unit is coupled to the third / fourth secondary windings and outputs the first / second low-voltage DC voltage to the first / second low-voltage battery. The full bridge diode rectifier is coupled to the fifth secondary winding. The full-bridge inverter outputs an AC output voltage.

Description

Technical Field

[0001] The invention relates to a multi-port bidirectional converter. Background Art

[0002] International efforts to combat global warming have begun, driving the advancement of electric vehicles (EVs) with the goal of reducing fuel consumption. For EV charging, a traditional approach of a combo onboard charger has been introduced. However, this approach brings challenges such as increased size and cost. In addition, to ensure safe redundant operation, multiple converters and several transformers are required to provide redundant outputs, which requires additional cost and space. Therefore, it becomes critical to find ways to reduce the cost and size of onboard chargers. Summary of the invention

[0003] According to one aspect of the present invention, a multi-port bidirectional converter is proposed, comprising a transformer, a primary full-bridge converter, a first high voltage (HV) power conversion unit, a second high voltage power conversion unit, a first low voltage (LV) power conversion unit, a second low voltage power conversion unit, a full-bridge diode rectifier and a full-bridge inverter. The transformer comprises a core, a first primary winding, a first secondary winding, a second secondary winding, a third secondary winding, a fourth secondary winding and a fifth secondary winding. The primary full-bridge converter is coupled to the first primary winding and receives an input voltage from a primary direct current (DC) voltage source. The first high voltage power conversion unit is coupled to the first secondary winding, and the first high voltage power conversion unit outputs a first high DC voltage to a first high voltage battery. The second high-voltage power conversion unit is coupled to the second secondary winding, and the second high-voltage power conversion unit outputs a second high-voltage DC voltage to a second high-voltage battery. The first low-voltage power conversion unit is coupled to the third secondary winding, and the first low-voltage power conversion unit outputs a first low-voltage DC voltage to a first low-voltage battery. The second low-voltage power conversion unit is coupled to the fourth secondary winding, and the second low-voltage power conversion unit outputs a second low-voltage DC voltage to a second low-voltage battery. The full-bridge diode rectifier is coupled to the fifth secondary winding. The full-bridge inverter is coupled to the full-bridge diode rectifier and outputs an alternating current (AC) output voltage to an AC load.

[0004] In order to better understand the above and other aspects of the present invention, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A block diagram of a multiple-port bidirectional converter in an on-board power unit (OPU) of an electric vehicle (EV) according to an embodiment of the present invention is shown;

[0006] Figure 2A block diagram illustrating an example of a multi-port bidirectional converter in an onboard power unit of an electric vehicle according to an embodiment of the present invention;

[0007] Figure 3 A block diagram of a multi-port bidirectional converter used in an on-board power unit of an electric vehicle is shown;

[0008] Figure 4 An example of a redundant mode of a multi-port bidirectional converter 300 applied to an on-board power unit of an electric vehicle according to an embodiment of the present invention is shown;

[0009] Figure 5 A block diagram showing a multi-port bidirectional converter used in an on-board power unit of an electric vehicle according to another embodiment of the present invention;

[0010] Fig. 6A A magnetic core structure of a transformer in a multi-port bidirectional converter in an on-board power unit of an electric vehicle according to another embodiment of the present invention is illustrated;

[0011] Figure 6B An example of a first primary winding in a multi-port bidirectional converter is shown;

[0012] Figure 6C An example of a first primary winding and a second primary winding in a multi-port bidirectional converter is shown.

[0013] Wherein, the reference numerals are:

[0014] 100,300:Multi-port bidirectional converter

[0015] 102,302: Transformer

[0016] 104,204: Input power conversion unit

[0017] 106,206: Load power conversion unit

[0018] 108,208,308,508: First high voltage power conversion unit

[0019] 110, 210, 310, 510: Second high voltage power conversion unit

[0020] 112,212,312,512: First low voltage power conversion unit

[0021] 114,214,314,514: Second low voltage power conversion unit

[0022] 116,316: The first high voltage battery

[0023] 118,318: Second high voltage battery

[0024] 120,320: First low voltage battery

[0025] 122,322: Second low voltage battery

[0026] 124: Power Supply

[0027] 126: AC load

[0028] 128,228:First microcontroller

[0029] 130,230: Second microcontroller

[0030] 132,232: Third microcontroller

[0031] 204_1: Input relay

[0032] 204_2: AC EMI filter

[0033] 204_3: Power Factor Correction Converter

[0034] 204_4: Large capacitor

[0035] 204_5: Primary LLC circuit

[0036] 206_1:V2L filter

[0037] 206_2: Single-phase inverter

[0038] 206_3,208_1,210_1,212_1,214_1: Secondary LLC circuit

[0039] 208_2,210_2: High voltage filter

[0040] 212_2,214_2: Low voltage filter

[0041] 234: AC voltage

[0042] 236: AC terminal

[0043] 238:V2L terminal

[0044] 240,242: High voltage terminals

[0045] 244,246: Low voltage terminal

[0046] 303: Primary Full-Bridge Converter

[0047] 305:Full-bridge diode rectifier

[0048] 307,507: Full-bridge inverter

[0049] 308_1: First high voltage full bridge converter

[0050] 308_2: First high voltage bidirectional buck / boost half-bridge converter

[0051] 310_1: Second high voltage full bridge converter

[0052] 310_2: Second high voltage bidirectional buck / boost half-bridge converter

[0053] 312_1: first synchronous rectifier

[0054] 312_2: First bidirectional low voltage buck / boost half-bridge converter

[0055] 314_1: Second synchronous rectifier

[0056] 314_2: Second bidirectional low voltage buck / boost half-bridge converter

[0057] 323:Primary DC Voltage Source

[0058] 326: AC load

[0059] 502: AC input circuit

[0060] 504:T-type converter

[0061] 532,534: High Voltage DC EMI Filter

[0062] 536,538:Low voltage DC EMI filter

[0063] 540:V2L EMI Filter

[0064] 542:AC EMI Filter

[0065] 544:V2L terminal

[0066] 600: Magnetic core

[0067] 602: first magnetic core column

[0068] 604: second magnetic core column

[0069] PW1: First primary winding

[0070] PW2: Second primary winding

[0071] SW1: First secondary winding

[0072] SW2: Second secondary winding

[0073] SW3: Third secondary winding

[0074] SW4: Fourth secondary winding

[0075] SW5: Fifth secondary winding

[0076] F1~F6: Fuse

[0077] C1~C12: Capacitor

[0078] T1~T18: switch

[0079] L1: primary resonant inductor

[0080] Lhv1: First high voltage buck / boost inductor

[0081] Lhv2: Second high voltage buck / boost inductor

[0082] Llv2: Second Low Voltage Buck / Boost Inductor

[0083] Llv1: First low voltage buck / boost inductor. DETAILED DESCRIPTION

[0084] The following will describe in detail various embodiments of the present invention, and will be illustrated with drawings. In addition to these detailed descriptions, the present invention can also be widely implemented in other embodiments, and any easy replacement, modification, and equivalent changes of the embodiments are included in the scope of the present invention and are subject to the claims. In the description of the specification, in order to give the reader a more complete understanding of the present invention, many specific details and implementation examples are provided; however, these specific details and implementation examples should not be regarded as limitations of the present invention. In addition, well-known steps or elements are not described in detail to avoid unnecessary limitations of the present invention.

[0085] Please refer to Figure 1 , which depicts a block diagram of a multiple-port bidirectional converter in an on-board power unit (OPU) of an electric vehicle (EV) according to an embodiment of the present invention. The OPU is responsible for managing the charging and discharging of the battery and providing power to various vehicle systems such as motors, electronic devices, etc. The multi-port bidirectional converter has multiple ports for connecting multiple power sources and loads. These power sources can be, for example, a public power grid, photovoltaic panels, wind turbines, batteries, fuel cells, etc. Figure 1As shown, a multi-port bidirectional converter 100 includes, for example, a transformer 102, an input power conversion unit 104, a load power conversion unit 106, a first high voltage (HV) power conversion unit 108, a second high voltage power conversion unit 110, a first low voltage (LV) power conversion unit 112, and a second low voltage power conversion unit 114. The first high voltage power conversion unit 108 outputs a first high DC voltage HVlt1 to a first high voltage battery 116. The second high voltage power conversion unit 110 outputs a second high DC voltage HVlt2 to a second high voltage battery 118. The first low voltage power conversion unit 112 outputs a first low voltage DC voltage LVlt1 to a first low voltage battery 120. The second low voltage power conversion unit 114 outputs a second low voltage DC voltage LVlt2 to a second low voltage battery 122. The input power conversion unit 104 receives input power from a power source 124. The load power conversion unit 106 can output power to an alternating current (AC) load 126.

[0086] For example, the power source 124 may be a utility grid. The multi-port bidirectional converter 100 may operate in a first operating mode. In the first operating mode, the input power conversion unit 104 may transfer power to the first high voltage battery 116, the second high voltage battery 118, the first low voltage battery 120, the second low voltage battery 122, and the AC load 126. Thus, in the first operating mode, the first high voltage battery 116 and the second high voltage battery 118 may receive power. The multi-port bidirectional converter 100 may also operate in a second operating mode. In the second operating mode, the first high voltage power conversion unit 108 and the second high voltage power conversion unit 110 may transfer power to the first low voltage battery 120, the second low voltage battery 122, the power source 124, and the AC load 126. Thus, in the second operating mode, the first high voltage battery 116 and the second high voltage battery 118 may transfer power. Since the first high voltage battery 116 and the second high voltage battery 118 may receive or transfer power, the multi-port bidirectional converter 100 is bidirectional.

[0087] The transformer 102 includes a magnetic core (not shown). Figure 1 ), a first primary winding PW1, a first secondary winding SW1, a second secondary winding SW2, a third secondary winding SW3, a fourth secondary winding SW4 and a fifth secondary winding SW5. The input power conversion unit 104 is coupled to the first primary winding PW1. The first high-voltage power conversion unit 108 is coupled to the first secondary winding SW1. The second high-voltage power conversion unit 110 is coupled to the second secondary winding SW2. The first low-voltage power conversion unit 112 is coupled to the third secondary winding SW3. The second low-voltage power conversion unit 114 is coupled to the fourth secondary winding SW4.

[0088] The first microcontroller (MCU) 128 controls the input power conversion unit 104 and the load power conversion unit 106. The second microcontroller 130 controls the first high voltage power conversion unit 108 and the first low voltage power conversion unit 112. The third microcontroller 132 controls the second high voltage power conversion unit 110 and the second low voltage power conversion unit 114.

[0089] Please refer to Figure 2 , Figure 2 A block diagram of an example of a multi-port bidirectional converter in an on-board power unit of an electric vehicle according to an embodiment of the present invention is depicted. The input power conversion unit 204, for example, includes an input relay 204_1, an AC electromagnetic interference (EMI) filter 204_2, a power factor correction (PFC) converter 204_3, a large capacitor 204_4, and a primary inductor-inductor-capacitor (LLC) circuit 204_5. The load power conversion unit 206, for example, includes a vehicle to load (V2L) filter 206_1, a single phase inverter 206_2, and a secondary LLC circuit 206_3. The first high-voltage power conversion unit 208, for example, includes a secondary LLC circuit 208_1 and a high-voltage filter 208_2. The second high-voltage power conversion unit 210, for example, includes a secondary LLC circuit 210_1 and a high-voltage filter 210_2. The first low voltage power conversion unit 212 includes, for example, a secondary LLC circuit 212_1 and a low voltage filter 212_2. The second low voltage power conversion unit 214 includes, for example, a secondary LLC circuit 214_1 and a low voltage filter 214_2.

[0090] The first microcontroller 228 controls the PFC converter 204_3 and the single-phase inverter 206_2. The second microcontroller 230 controls the secondary LLC circuit 208_1 and the secondary LLC circuit 212_1. The third microcontroller 232 controls the secondary LLC circuit 210_1 and the secondary LLC circuit 214_1.

[0091] The AC voltage 234 is input to the input power conversion unit 204 via the AC terminal 236. The load power conversion unit 206 outputs power to the V2L terminal 238. The first high-voltage power conversion unit 208 outputs voltage to the high-voltage terminal 240. The second high-voltage power conversion unit 210 outputs voltage to the high-voltage terminal 242. The first low-voltage power conversion unit 212 outputs voltage to the low-voltage terminal 244. The second low-voltage power conversion unit 214 outputs voltage to the low-voltage terminal 246.

[0092] Please refer to Figure 3 , Figure 3 A block diagram of a multi-port bidirectional converter used in an on-board power unit of an electric vehicle is shown. The multi-port bidirectional converter 300 includes a transformer 302, a primary full-bridge converter 303, a first high-voltage power conversion unit 308, a second high-voltage power conversion unit 310, a first low-voltage power conversion unit 312, a second low-voltage power conversion unit 314, a full-bridge diode rectifier 305, and a full-bridge inverter 307.

[0093] The transformer 302 includes a core (not shown) Figure 3 ), a first primary winding PW1, a first secondary winding SW1, a second secondary winding SW2, a third secondary winding SW3, a fourth secondary winding SW4, and a fifth secondary winding SW5. The primary full-bridge converter 303 is coupled to the first primary winding PW1 and receives an input voltage Vin from the primary DC voltage source 323.

[0094] The first high voltage power conversion unit 308 is coupled to the first secondary winding SW1, and outputs a first high DC voltage HVlt1 to the first high voltage battery 316. The second high voltage power conversion unit 310 is coupled to the second secondary winding SW2, and outputs a second high DC voltage HVlt2 to the second high voltage battery 318. The first low voltage power conversion unit 312 is coupled to the third secondary winding SW3, and outputs a first low DC voltage LVlt1 to the first low voltage battery 320. The second low voltage power conversion unit 314 is coupled to the fourth secondary winding SW4, and outputs a second low DC voltage LVlt2 to the second low voltage battery 322. The full bridge diode rectifier 305 is coupled to the fifth secondary winding SW5. The full bridge inverter 307 is coupled to the full bridge diode rectifier 305 and outputs an AC output voltage Vac to the AC load 326.

[0095] The multi-port bidirectional converter 300 further includes a first fuse F1, a second fuse F2, a third fuse F3, a fourth fuse F4, a fifth fuse F5, and a sixth fuse F6. The first fuse F1 is coupled between the first primary winding PW1 and the primary full-bridge converter 303. The second fuse F2 is coupled between the first secondary winding SW1 and the first high-voltage power conversion unit 308. The third fuse F3 is coupled between the second secondary winding SW2 and the second high-voltage power conversion unit 310. The fourth fuse F4 is coupled between the third secondary winding SW3 and the first low-voltage power conversion unit 312. The fifth fuse F5 is coupled between the fourth secondary winding SW4 and the second low-voltage power conversion unit 314. The sixth fuse F6 is coupled between the fifth secondary winding SW5 and the full-bridge diode rectifier 305.

[0096] Fuses F1 to F6 can be used to isolate a failed or faulty power conversion unit. For example, when too much current flows through the first high-voltage power conversion unit 308, fuse F2 melts to stop the current from flowing, and fuse F2 isolates the first high-voltage power conversion unit 308 from other power conversion units and other components of the multi-port bidirectional converter 300. Therefore, other power conversion units and other components of the multi-port bidirectional converter 300 can be protected.

[0097] The multi-port bidirectional converter 300 further includes a first capacitor C1 and a primary resonant inductor L1. One end of the first capacitor C1 is coupled to one end of the first primary winding PW1. One end of the primary resonant inductor L1 is coupled to the other end of the first primary winding PW1. One end of the primary full-bridge converter 303 is coupled to the other end of the first capacitor C1. The other end of the primary full-bridge converter 303 is coupled to the other end of the primary resonant inductor L1.

[0098] The first high-voltage power conversion unit 308 includes a first high-voltage full-bridge converter 308_1, a second capacitor C2 and a third capacitor C3. The second capacitor C2 is coupled between the first high-voltage full-bridge converter 308_1 and the first secondary winding SW1. The third capacitor C3 is coupled between two terminals of the first high-voltage full-bridge converter 308_1.

[0099] The first high-voltage power conversion unit 308 also includes a first high-voltage bidirectional buck / boost half-bridge converter 308_2, coupled to the third capacitor C3. The first high-voltage power conversion unit 308 also includes a first high-voltage buck / boost inductor Lhv1 and a fourth capacitor C4. The first high-voltage buck / boost inductor Lhv1 is coupled to the first high-voltage bidirectional buck / boost half-bridge converter 308_2, and the fourth capacitor C4 is coupled to the first high-voltage buck / boost inductor Lhv1. The voltage of the fourth capacitor C4 is used as the first high DC voltage HVlt1.

[0100] The second high-voltage power conversion unit 310 includes a second high-voltage full-bridge converter 310_1, a fifth capacitor C5, and a sixth capacitor C6. The fifth capacitor C5 is coupled between the second high-voltage full-bridge converter 310_1 and the second secondary winding SW2. The sixth capacitor C6 is coupled between two terminals of the second high-voltage full-bridge converter 310_1. The second high-voltage power conversion unit 310 also includes a second high-voltage bidirectional buck / boost half-bridge converter 310_2, coupled to the sixth capacitor C6.

[0101] The second high-voltage power conversion unit 310 further includes a second high-voltage buck / boost inductor Lhv2 and a seventh capacitor C7. The second high-voltage buck / boost inductor Lhv2 is coupled to the second high-voltage bidirectional buck / boost half-bridge converter 310_2, and the seventh capacitor C7 is coupled to the second high-voltage buck / boost inductor Lhv2. The voltage of the seventh capacitor C7 is used as the second high DC voltage HVlt2.

[0102] The first low-voltage power conversion unit 312 includes a first synchronous rectifier (SR) 312_1 and an eighth capacitor C8. The eighth capacitor C8 is coupled to the first synchronous rectifier 312_1. The first low-voltage power conversion unit 312 also includes a first bidirectional low-voltage buck / boost half-bridge converter 312_2, a first low-voltage buck / boost inductor Llv1 and a ninth capacitor C9. The first low-voltage buck / boost inductor Llv1 is coupled between the first bidirectional low-voltage buck / boost half-bridge converter 312_2 and the ninth capacitor C9. The voltage of the ninth capacitor C9 is used as the first low-voltage DC voltage LVlt1.

[0103] The second low-voltage power conversion unit 314 includes a second synchronous rectifier 314_1 and a tenth capacitor C10. The tenth capacitor C10 is coupled to the second synchronous rectifier 314_1. The second low-voltage power conversion unit 314 also includes a second bidirectional low-voltage buck / boost half-bridge converter 314_2, a second low-voltage buck / boost inductor Llv2 and an eleventh capacitor C11. The second low-voltage buck / boost inductor Llv2 is coupled between the second bidirectional low-voltage buck / boost half-bridge converter 314_2 and the eleventh capacitor C11. The voltage of the eleventh capacitor C11 is used as the second low-voltage DC voltage LVlt2.

[0104] The multi-port bidirectional converter 300 further includes a twelfth capacitor C12. One end of the full-bridge diode rectifier 305 is coupled to one end of the fifth secondary winding SW5. One end of the full-bridge diode rectifier 305 is coupled to the other end of the fifth secondary winding SW5. The twelfth capacitor C12 is coupled between two ends of the full-bridge diode rectifier 305, and the full-bridge inverter 307 is coupled to the twelfth capacitor C12.

[0105] The number of turns of the first secondary winding SW1 is greater than the number of turns of the third secondary winding SW3. Therefore, the voltage value of the first high DC voltage HVlt1 is greater than the voltage value of the first low DC voltage LVlt1. Similarly, the number of turns of the second secondary winding SW2 is greater than the number of turns of the fourth secondary winding SW4. Therefore, the voltage value of the second high DC voltage HVlt2 is greater than the voltage value of the second low DC voltage LVlt2. For example, the number of turns of the first secondary winding SW1 can be 14, the number of turns of the second secondary winding SW2 can be 14, the number of turns of the third secondary winding SW3 can be 2, and the number of turns of the fourth secondary winding SW4 can be 2.

[0106] When the multi-port bidirectional converter 300 operates in the first operation mode, which is, for example, the AC charging mode, the primary full-bridge converter 303 transfers electric energy to the first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, and the AC load 326. That is, the electric energy input from the AC power grid is converted into an input voltage Vin, which is a DC voltage, for example, by an AC / DC converter, a PFC converter, or a T-type converter. Then, the input voltage Vin is input to the primary full-bridge converter 303. By turning on and off switches T1 to T4 in a specific sequence, the primary full-bridge converter 303 generates an AC voltage and inputs it to the first primary winding PW1 through the first capacitor C1 and the primary resonant inductor L1. Then, the electric energy is transmitted from the first primary winding PW1 to the first secondary winding SW1, the second secondary winding SW2, the third secondary winding SW3, the fourth secondary winding SW4, and the fifth secondary winding SW5 through magnetic coupling in the transformer 302. Afterwards, the electric energy is transferred to the first high voltage battery 316, the second high voltage battery 318, the first low voltage battery 320, the second low voltage battery 322 and the AC load 326 through the first high voltage power conversion unit 308, the second high voltage power conversion unit 310, the first low voltage power conversion unit 312, the second low voltage power conversion unit 314, the full-bridge diode rectifier 305 and the full-bridge inverter 307. The first high voltage battery 316, the second high voltage battery 318, the first low voltage battery 320, the second low voltage battery 322 and the AC load 326 are respectively coupled to the first secondary winding SW1 to the fifth secondary winding SW5.

[0107] In order to convert the input voltage Vin into an AC voltage in the primary full-bridge converter 303, switches T1 and T4 may be turned on, and switches T2 and T3 may be turned off, for example, in a first time segment. For example, the first time segment may be a half cycle of a switching period of switches T1 to T4. Thereafter, switches T1 and T4 are turned off, and switches T2 and T3 are turned on, in a second time segment. The first time segment and the second time segment repeat and alternate. The switching frequency of switches T1 to T4 may be adjusted, or the first time segment and the second time segment may be adjusted to generate an AC voltage of different frequencies or amplitudes. For example, the first time segment may be the first half cycle of a switching period of switches T1 to T4, and the second time segment may be the second half cycle of a switching period of switches T1 to T4.

[0108] The operation of the first high-voltage power conversion unit 308 is described as follows. By turning on and off switches T5 to T8 in a specific order, the AC voltage generated by the first secondary winding SW1 is converted into a DC voltage across the third capacitor C3. For example, during the positive voltage period of the AC voltage generated by the first secondary winding SW1, switches T5 and T8 are turned on, and switches T6 and T7 are turned off to charge the third capacitor C3, so that the voltage of the third capacitor C3 increases. Then, during the negative voltage period of the AC voltage generated by the first secondary winding SW1, switches T6 and T7 are turned on, and switches T5 and T8 are turned off to charge the third capacitor C3, so that the voltage of the third capacitor C3 continues to increase.

[0109] Afterwards, by turning on switch T9, the electric energy in the third capacitor C3 is transferred to the fourth capacitor C4. When switch T10 is turned on, the fourth capacitor C4 is discharged, so that the voltage of the fourth capacitor C4 is reduced. The on-time of switch T9 and the on-time of switch T10 determine the voltage of the fourth capacitor C4. By controlling the on-time of switches T9 and T10 or controlling the on-time ratio of switches T9 and T10, the voltage of the fourth capacitor C4 can be determined. By controlling the on-time of different switches T9 and T10 or controlling the on-time ratio of different switches T9 and T10, different voltages of the fourth capacitor C4 can be achieved, and a wide voltage range of the fourth capacitor C4 is provided. In some embodiments, when the wide voltage range of the fourth capacitor C4 is not required, the first high-voltage bidirectional buck / boost half-bridge converter 308_2 can be omitted.

[0110] The electric energy stored in the fourth capacitor C4 is used to charge the first high voltage battery 316. The above process is repeated during the charging of the first high voltage battery 316. The operation of the second high voltage power conversion unit 310 is similar to that of the first high voltage power conversion unit 308 and will not be repeated here.

[0111] The operation of the first low voltage power conversion unit 312 is described as follows. By turning on and off switches T11 and T12 in a specific order, the AC voltage generated by the third secondary winding SW3 is converted into a DC voltage across the eighth capacitor C8. For example, during the positive voltage period of the AC voltage generated by the third secondary winding SW3, one of the switches T11 and T12 is turned on to charge the eighth capacitor C8. Then, during the negative voltage period of the AC voltage generated by the third secondary winding SW3, the other of the switches T11 and T12 is turned on to charge the eighth capacitor C8. Afterwards, by turning on switch T13, the electric energy in the eighth capacitor C8 is transferred to the ninth capacitor C9, and the energy is stored in the first low voltage buck / boost inductor Llv1. When switch T13 is not turned on and switch T14 is turned on, the ninth capacitor C9 is discharged, the energy in the first low voltage buck / boost inductor Llv1 is released, and the voltage of the ninth capacitor C9 is reduced. The conduction time of switch T13 and the conduction time of switch T14 determine the voltage of the ninth capacitor C9. By controlling the conduction time of switches T13 and T14 or controlling the conduction time ratio of switches T13 and T14, the voltage of the ninth capacitor C9 can be determined. By providing different conduction times of switches T13 and T14 or different conduction time ratios of switches T13 and T14, different voltages of the ninth capacitor C9 can be achieved, and a wide voltage range of the ninth capacitor C9 can be provided. The electric energy stored in the ninth capacitor C9 is used to charge the first low-voltage battery 320. In some embodiments, when the wide voltage range of the ninth capacitor C9 is not required, the first bidirectional low-voltage buck / boost half-bridge converter 312_2 can be omitted.

[0112] The above process is repeated during the charging of the first low voltage battery 320. The operation of the second low voltage power conversion unit 314 is similar to that of the first low voltage power conversion unit 312 and will not be repeated here.

[0113] The operation of the full-bridge diode rectifier 305 and the full-bridge inverter 307 is described as follows. When the AC voltage output by the fifth secondary winding SW5 is positive, the diode D1 and the diode D4 are turned on, and the current flows through the diode D1 and the diode D4 to charge the twelfth capacitor C12. When the AC voltage output by the fifth secondary winding SW5 is negative, the diode D2 and the diode D3 are turned on, and the current flows through the diode D2 and the diode D3 to charge the twelfth capacitor C12.

[0114] Then, in the first time segment, switches T15 and T18 are turned on, and switches T16 and T17 are turned off. In the second time segment, switches T15 and T18 are turned off, and switches T16 and T17 are turned on. In this way, the DC voltage across the twelfth capacitor C12 is converted into an AC output voltage Vac.

[0115] In addition, the switches T1 to T18 can be implemented by transistors. Other switches shown in the drawings in the present invention can also be implemented by transistors.

[0116] When the multi-port bidirectional converter 300 operates in a second operating mode, such as a reverse operating mode, at least one of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transmits power to at least one of the first low-voltage battery 320, the second low-voltage battery 322, the primary DC voltage source 323 and the AC load 326.

[0117] Taking the first high-voltage power conversion unit 308 as an example, the power stored in the first high-voltage battery 316 is transferred to the fourth capacitor C4. Then, by turning on the switch T9, the power in the fourth capacitor C4 is transferred to the third capacitor C3. The conduction time of the switch T9 determines the voltage of the third capacitor C3. When the switch T10 is turned on, the energy is stored in the first high-voltage buck / boost inductor Lhv1. When the switch T10 is not turned on and the switch T9 is turned on, the energy in the first high-voltage buck / boost inductor Lhv1 is released and the third capacitor C3 is charged. The voltage of the third capacitor C3 is determined by controlling the length of time that the switches T9 and T10 are turned on or off.

[0118] By turning on and off switches T5 to T8 in a specific order, an AC voltage output to the first secondary winding SW1 is generated. For example, switches T5 and T8 are turned on, and switches T6 and T7 are not turned on, to generate a positive voltage of the AC voltage of the first secondary winding SW1. Then, switches T6 and T7 are turned on, and switches T5 and T8 are not turned on, to generate a negative voltage of the AC voltage of the first secondary winding SW1. The electric energy in the first secondary winding SW1 is transmitted to at least one of the second secondary winding SW2, the third secondary winding SW3, the fourth secondary winding SW4, the fifth secondary winding SW5 and the first primary winding PW1 through the magnetic coupling of the transformer. Then, the electrical energy in at least one of the second secondary winding SW2, the third secondary winding SW3, the fourth secondary winding SW4, the fifth secondary winding SW5 and the first primary winding PW1 is transferred to at least one of the second high voltage battery 318, the first low voltage battery 320, the second low voltage battery 322, the primary DC voltage source 323 and the AC load 326.

[0119] In addition, when one of the first high-voltage power conversion unit 308, the second high-voltage power conversion unit 310, the first low-voltage power conversion unit 312, or the second low-voltage power conversion unit 314 fails, the multi-port bidirectional converter 300 may operate in a third operating mode, such as a redundant mode. When the first high-voltage power conversion unit 308 or the second high-voltage power conversion unit 310 fails, the other of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transmits power to at least one of the first low-voltage battery 320 and the second low-voltage battery 322. In addition, when one of the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314 fails, at least one of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transmits power to the other of the first low-voltage battery 320 or the second low-voltage battery 322 corresponding to the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314. The redundant mode of the multi-port bidirectional converter 300 will be in Figure 4 Further explanation in.

[0120] Please refer to Figure 4 , Figure 4 FIG. 2 shows an example of a redundant mode of a multi-port bidirectional converter 300 applied to an on-board power unit of an electric vehicle according to an embodiment of the present invention. Figure 4 In the table shown in FIG. 1 , the mark “IN” indicates that the corresponding unit is an input unit that provides power to other units. The mark “OUT” indicates that the corresponding unit is an output unit that receives power from other units. The mark “X” indicates that the corresponding unit does not operate.

[0121] In case 1, the first high voltage battery 316 fails and the first high voltage power conversion unit 308 does not operate. Alternatively, in case 1, the first high voltage power conversion unit 308 fails. The second high voltage power conversion unit 310 supplies power to the first low voltage power conversion unit 312 and the second low voltage power conversion unit 314. Then, the first low voltage power conversion unit 312 and the second low voltage power conversion unit 314 supply power to the first low voltage battery 320 and the second low voltage battery 322, respectively.

[0122] In case 2, the second high voltage battery 318 fails and the second high voltage power conversion unit 310 does not operate. Alternatively, in case 2, the second high voltage power conversion unit 310 fails. The first high voltage power conversion unit 308 supplies power to the first low voltage power conversion unit 312 and the second low voltage power conversion unit 314. Then, the first low voltage power conversion unit 312 and the second low voltage power conversion unit 314 supply power to the first low voltage battery 320 and the second low voltage battery 322, respectively.

[0123] In case 3, the first low voltage power conversion unit 312 fails and does not operate. The first high voltage power conversion unit 308 and the second high voltage power conversion unit 310 both supply power to the second low voltage power conversion unit 314. Then, the second low voltage power conversion unit 314 supplies power to the second low voltage battery 322.

[0124] In case 4, the second low voltage battery 322 fails and the second low voltage power conversion unit 314 does not operate. Alternatively, in case 4, the second low voltage power conversion unit 314 fails. Both the first high voltage power conversion unit 308 and the second high voltage power conversion unit 310 supply power to the first low voltage power conversion unit 312. Then, the first low voltage power conversion unit 312 supplies power to the first low voltage battery 320.

[0125] In case 5, both the first high voltage battery 316 and the first low voltage battery 320 fail, and both the first high voltage power conversion unit 308 and the first low voltage power conversion unit 312 do not operate. Alternatively, in case 5, the first high voltage power conversion unit 308 and the first low voltage power conversion unit 312 fail. The second high voltage power conversion unit 310 and the second low voltage power conversion unit 314 operate normally. The second high voltage power conversion unit 310 supplies power to the second low voltage power conversion unit 314, and the second low voltage power conversion unit 314 supplies power to the second low voltage battery 322.

[0126] In case 6, both the second high voltage battery 318 and the second low voltage battery 322 fail, and both the second high voltage power conversion unit 310 and the second low voltage power conversion unit 314 do not operate. Alternatively, in case 6, the second high voltage power conversion unit 310 and the second low voltage power conversion unit 314 fail. The first high voltage power conversion unit 308 and the first low voltage power conversion unit 312 operate normally. The first high voltage power conversion unit 308 supplies power to the first low voltage power conversion unit 312, and the first low voltage power conversion unit 312 supplies power to the first low voltage battery 320.

[0127] In summary, when the multi-port bidirectional converter 300 operates in the first operation mode (or AC charging mode), the primary full-bridge converter 303 transfers power received from the AC grid to the first high voltage battery 316, the second high voltage battery 318, the first low voltage battery 320, the second low voltage battery 322, and the AC load 326. When the multi-port bidirectional converter 300 operates in the second operation mode (or reverse operation mode), at least one of the first high voltage power conversion unit 308 and the second high voltage power conversion unit 310 transfers power to at least one of the first low voltage battery 320, the second low voltage battery 322, the primary DC voltage source 323, and the AC load 326. The reverse operation mode provides flexible power sharing between the first high voltage battery 316, the second high voltage battery 318, the first low voltage battery 320, and the second low voltage battery 322. The reverse operation mode allows automatic battery balancing. In the event of failure or malfunction of any power conversion unit or battery, the multi-port bidirectional converter 300 will operate in the third operation mode (or redundant mode). Through the redundant mode, when any power conversion unit or battery fails, other power conversion units can be used to charge other batteries. Even if the electric vehicle has been running for a long time and cannot find a charging station, the multi-port bidirectional converter 300 operating in the redundant mode can be used to charge the battery using other power conversion units that can operate normally. Therefore, the convenience of use is improved.

[0128] Please refer to Figure 5 , Figure 5 FIG. 5 shows a block diagram of a multi-port bidirectional converter used in an on-board power unit of an electric vehicle according to another embodiment of the present invention. Figure 3 The difference between the multi-port bidirectional converter 300 in FIG. 5 is that the multi-port bidirectional converter 500 further includes an AC input circuit 502, a T-type converter 504, a high-voltage DC EMI filter 532, a high-voltage DC EMI filter 534, a low-voltage DC EMI filter 536, a low-voltage DC EMI filter 538, and a V2LEMI filter 540. In the AC input circuit 502, the three-phase signals L1, L2, and L3 of the AC input or the grid and the neutral point signal N are transmitted to the AC EMI filter 542. Figure 5 The mark "PE" in represents grounding. Then, these phase signals are sent to T-type converter 504 to be converted into direct current voltage.

[0129] In addition, the DC voltage output from the first high-voltage power conversion unit 508 is transmitted to the high-voltage DC EMI filter 532 to generate a first high DC voltage HVlt1'. The DC voltage output from the second high-voltage power conversion unit 510 is transmitted to the high-voltage DC EMI filter 534 to generate a second high DC voltage HVlt2'. The DC voltage output from the first low-voltage power conversion unit 512 is transmitted to the low-voltage DC EMI filter 536 to generate a first low DC voltage LVlt1'. The DC voltage output from the second low-voltage power conversion unit 514 is transmitted to the low-voltage DC EMI filter 538 to generate a second low DC voltage LVlt2'. The AC voltage output from the full-bridge inverter 507 is transmitted to the V2L EMI filter 540 and then transmitted to the V2L terminal 544.

[0130] Please refer to FIG. 6A to FIG. 6C , Fig. 6A The magnetic core structure of a transformer in a multi-port bidirectional converter in an on-board power unit of an electric vehicle according to another embodiment of the present invention is shown. Figure 6B An example of a first primary winding in a multi-port bidirectional converter is shown. Figure 6C An example of a first primary winding and a second primary winding in a multi-port bidirectional converter is shown.

[0131] like Fig. 6A As shown, the magnetic core 600 of the transformer 102 or 302 includes a first magnetic core column 602 and a second magnetic core column 604. Figure 6B As shown, the first primary winding PW1 is wound around the first magnetic core column 602. In one embodiment, as shown in FIG. Figure 6C As shown, the transformer 102 or 302 further includes a second primary winding PW2, the first primary winding PW1 is wound on the first magnetic core leg 602, and the second primary winding PW2 is wound on the second magnetic core leg 604. The first primary winding PW1 and the second primary winding PW2 are coupled in parallel. The first primary winding PW1 and the second primary winding PW2 coupled in parallel can receive an input voltage Vin from a primary DC voltage source or power supply.

[0132] According to one embodiment of the present invention, a multi-port bidirectional converter proposes an integrated power supply with multiple ports to provide redundant operation for a combined on-board charger having 1 primary AC input port, 2 high-voltage DC output ports, 2 low-voltage DC output ports, and 1 V2L output port. Power between these multiple ports can be flexibly shared by magnetically coupling through a shared transformer with multiple windings. Compared to another converter having 6 transformers for 6 ports, a multi-port bidirectional converter according to one embodiment of the present invention will save 5 transformers and 5 corresponding full-bridge converters. Therefore, the cost and size of the multi-port bidirectional converter according to an embodiment of the present invention can be reduced by reducing the number of key components.

[0133] The multi-port bidirectional converter according to an embodiment of the present invention also provides bidirectional power flow between these multiple ports, and provides wide output voltage range regulation for high-voltage DC batteries and low-voltage DC batteries, or high-voltage DC battery groups and low-voltage DC battery groups. In addition, when some batteries fail or some power conversion units fail, the multi-port bidirectional converter according to an embodiment of the present invention can achieve redundant operation.

[0134] In addition, according to an embodiment of the present invention, the multi-port bidirectional converter has the advantages of high power efficiency, power flow control flexibility and wide voltage range operation. According to an embodiment of the present invention, the multi-port bidirectional converter can be operated at a fixed switching frequency to provide a fixed output voltage at each port. According to an embodiment of the present invention, the multi-port bidirectional converter can be designed to operate at a frequency slightly higher than the resonant frequency (corresponding to the capacitor and inductor in the multi-port bidirectional converter) to achieve zero voltage switching (Zero Voltage Switching, ZVS) of the power conversion unit and reduce the magnetization loss of the transformer. Therefore, the efficiency of the multi-port bidirectional converter is optimized.

[0135] In addition, according to one embodiment of the present invention, the multi-port bidirectional converter is able to achieve droop control through flexible power sharing. Droop control can be performed by controlling the power conversion unit through the MCU. Droop control involves reducing the voltage or frequency when the grid load increases. To ensure grid stability, the multi-port bidirectional converter can adopt flexible power sharing between the power supply, high-voltage battery, low-voltage battery and AC load as needed to mitigate the impact of the grid. By dynamically adjusting the output power of the power conversion unit to achieve shared power use, the grid load can be reduced, and the grid load balance and stability can be effectively managed.

[0136] In addition, the bidirectional buck / boost half-bridge converter in the multi-port bidirectional converter according to an embodiment of the present invention is used to provide a wide voltage range at the high voltage port and the low voltage port. Therefore, the high voltage battery and the low voltage battery or the high voltage battery pack and the low voltage battery pack can have a wide voltage range and can accommodate various battery voltage ranges from different automobile manufacturers.

[0137] Furthermore, a multi-port bidirectional converter according to an embodiment of the present invention may include a transformer with additional secondary windings and may include additional power conversion units to connect to an energy source, such as a solar photovoltaic module or a wind turbine.

[0138] In summary, although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. A person skilled in the art of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the patent application.

Claims

1. A multi-port bidirectional converter, characterized in that: include: a transformer, a primary full-bridge converter, a first high-voltage power conversion unit, a second high-voltage power conversion unit, a first low-voltage power conversion unit, a second low-voltage power conversion unit, a full-bridge diode rectifier and a full-bridge inverter; Wherein, the transformer comprises a magnetic core, a first primary winding, a first secondary winding, a second secondary winding, a third secondary winding, a fourth secondary winding and a fifth secondary winding; Wherein, the primary full-bridge converter is coupled to the first primary winding and receives an input voltage from a primary DC voltage source; Wherein, the first high-voltage power conversion unit is coupled to the first secondary winding, and the first high-voltage power conversion unit outputs a first high direct current voltage to a first high-voltage battery; The second high-voltage power conversion unit is coupled to the second secondary winding, and the second high-voltage power conversion unit outputs a second high-voltage DC voltage to a second high-voltage battery; Wherein, the first low-voltage power conversion unit is coupled to the third secondary winding, and the first low-voltage power conversion unit outputs a first low-voltage direct current voltage to a first low-voltage battery; The second low-voltage power conversion unit is coupled to the fourth secondary winding, and the second low-voltage power conversion unit outputs a second low-voltage DC voltage to a second low-voltage battery; wherein the full-bridge diode rectifier is coupled to the fifth secondary winding; The full-bridge inverter is coupled to the full-bridge diode rectifier and outputs an AC output voltage to an AC load.

2. The multi-port bidirectional converter as claimed in claim 1, wherein: In a first operating mode, the primary full-bridge converter transfers electrical energy to the first high-voltage battery, the second high-voltage battery, the first low-voltage battery, the second low-voltage battery, and the AC load; In a second operating mode, at least one of the first high-voltage power conversion unit and the second high-voltage power conversion unit transfers electrical energy to at least one of the first low-voltage battery, the second low-voltage battery, the primary DC voltage source and the AC load.

3. The multi-port bidirectional converter as claimed in claim 1, wherein: The magnetic core comprises a first magnetic core column and a second magnetic core column; The transformer further includes a second primary winding, the first primary winding is wound on the first magnetic core column, and the second primary winding is wound on the second magnetic core column.

4. The multi-port bidirectional converter as claimed in claim 3, wherein: The first primary winding and the second primary winding are connected in parallel.

5. The multi-port bidirectional converter as claimed in claim 1, wherein: The number of turns of the first secondary winding is greater than the number of turns of the third secondary winding.

6. The multi-port bidirectional converter as claimed in claim 2, wherein: When one of the first high-voltage power conversion unit and the second high-voltage power conversion unit fails, the other of the first high-voltage power conversion unit and the second high-voltage power conversion unit transfers electrical energy to at least one of the first low-voltage battery and the second low-voltage battery.

7. The multi-port bidirectional converter as claimed in claim 2, wherein: When one of the first low voltage power conversion unit and the second low voltage power conversion unit fails, at least one of the first high voltage power conversion unit and the second high voltage power conversion unit transfers electrical energy to the first low voltage battery or the second low voltage battery corresponding to the other of the first low voltage power conversion unit and the second low voltage power conversion unit.

8. The multi-port bidirectional converter as claimed in claim 1, wherein: Also includes: a first fuse coupled between the first primary winding and the primary full-bridge converter; a second fuse coupled between the first secondary winding and the first high-voltage power conversion unit; a third fuse coupled between the second secondary winding and the second high-voltage power conversion unit; a fourth fuse coupled between the third secondary winding and the first low-voltage power conversion unit; a fifth fuse coupled between the fourth secondary winding and the second low-voltage power conversion unit; and A sixth fuse is coupled between the fifth secondary winding and the full-bridge diode rectifier.

9. The multi-port bidirectional converter as claimed in claim 1, wherein: Also includes a first capacitor and a primary resonant inductor; Wherein, one end of the first capacitor is coupled to one end of the first primary winding, and one end of the primary resonant inductor is coupled to the other end of the first primary winding; One end of the primary full-bridge converter is coupled to the other end of the first capacitor, and the other end of the primary full-bridge converter is coupled to the other end of the primary resonant inductor.

10. The multi-port bidirectional converter as claimed in claim 9, wherein: The first high-voltage power conversion unit includes a first high-voltage full-bridge converter, a second capacitor and a third capacitor. The second capacitor is coupled between the first high-voltage full-bridge converter and the first secondary winding, and the third capacitor is coupled between two endpoints of the first high-voltage full-bridge converter.

11. The multi-port bidirectional converter as claimed in claim 10, wherein: The first high-voltage power conversion unit further includes a first high-voltage bidirectional buck / boost half-bridge converter. The first high-voltage bidirectional buck / boost half-bridge converter is coupled to the third capacitor.

12. The multi-port bidirectional converter as claimed in claim 11, wherein: The first high-voltage power conversion unit also includes a first high-voltage buck / boost inductor and a fourth capacitor. The first high-voltage buck / boost inductor is coupled to the first high-voltage bidirectional buck / boost half-bridge converter, and the fourth capacitor is coupled to the first high-voltage buck / boost inductor. The voltage of the fourth capacitor is the first high DC voltage.

13. The multi-port bidirectional converter as claimed in claim 12, wherein: The second high-voltage power conversion unit includes a second high-voltage full-bridge converter, a fifth capacitor and a sixth capacitor. The fifth capacitor is coupled between the second high-voltage full-bridge converter and the second secondary winding, and the sixth capacitor is coupled between two endpoints of the second high-voltage full-bridge converter.

14. The multi-port bidirectional converter as claimed in claim 13, wherein: The second high-voltage power conversion unit further includes a second high-voltage bidirectional buck / boost half-bridge converter. The second high-voltage bidirectional buck / boost half-bridge converter is coupled to the sixth capacitor.

15. The multi-port bidirectional converter as claimed in claim 14, wherein: The second high-voltage power conversion unit also includes a second high-voltage buck / boost inductor and a seventh capacitor. The second high-voltage buck / boost inductor is coupled to the second high-voltage bidirectional buck / boost half-bridge converter. The seventh capacitor is coupled to the second high-voltage buck / boost inductor. The voltage of the seventh capacitor is the second high DC voltage.

16. The multi-port bidirectional converter as claimed in claim 15, wherein: The first low-voltage power conversion unit includes a first synchronous rectifier and an eighth capacitor, and the eighth capacitor is coupled to the first synchronous rectifier.

17. The multi-port bidirectional converter as claimed in claim 16, wherein: The first low-voltage power conversion unit also includes a first low-voltage bidirectional buck / boost half-bridge converter, a first low-voltage buck / boost inductor and a ninth capacitor. The first low-voltage buck / boost inductor is coupled between the first low-voltage bidirectional buck / boost half-bridge converter and the ninth capacitor, and the voltage of the ninth capacitor is the first low-voltage DC voltage.

18. The multi-port bidirectional converter as claimed in claim 17, wherein: The second low-voltage power conversion unit includes a second synchronous rectifier and a tenth capacitor, and the tenth capacitor is coupled to the second synchronous rectifier.

19. The multi-port bidirectional converter as claimed in claim 18, wherein: The second low-voltage power conversion unit also includes a second low-voltage bidirectional buck / boost half-bridge converter, a second low-voltage buck / boost inductor and an eleventh capacitor. The second low-voltage buck / boost inductor is coupled between the second low-voltage bidirectional buck / boost half-bridge converter and the eleventh capacitor, and the voltage of the eleventh capacitor is the second low-voltage DC voltage.

20. The multi-port bidirectional converter as claimed in claim 19, wherein: Also includes a twelfth capacitor; One end of the full-bridge diode rectifier is coupled to one end of the fifth secondary winding, one end of the full-bridge diode rectifier is coupled to the other end of the fifth secondary winding, the twelfth capacitor is coupled between two ends of the full-bridge diode rectifier, and the full-bridge inverter is coupled to the twelfth capacitor.

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